Sound recording and reproducing



G. CLUTIER ET AL SOUND RECORDING AND REPRODUCING July 17, 1951 2 Sheets-Sheet 1 Filed Sept. 2, 1947 July 17, 195] G. CLUTIER ETAL 2,561,181

SOUND RECORDING AND REPRODUCING Filed Sept. 2, 1947 2 Sheets-Sheet 2 Patented July 17, 1951 SOUND RECORDING AND REPRQDUCING Guy Clutier, Paris, and Marc Assada, Villefranche-sur-Saone, France Application September 2, 1947, Serial No. 771,660 In France September 9, 1946 6 Claims. (01. 179-14M).3)

It has already been proposed to obtain a socalled sound relief effect for improving the grade of a moving picture show by providing in the projecting hall a so-called sound environment or sound atmosphere which is obtained by producing ground noises through suitably placed loud-speakers.

Now, all the means disclosed theretofore for obtaining this result are promised to failure inasmuch as these means require a deep transformation of the cinematographic films themselves, as also of the recording and reproducing apparatuses. As a matter of fact, one of the means which are the most readily apparent to the mind consists in providing on the film one or more supplementary sound tracks for energizing the means which are to produce the sounds atmosphere and this leads to a transformation of the apparatuses operating with such films.

Our invention allows a very easy solving of the problem of the automatic control of a sound atmosphere without it being necessary to modify in any manner whateveneither the films or the view taking means, the sound recording means or the projecting and sound producing means existing nowadays.

The method forming the basis of the invention is remarkable chiefly through the fact that, on one hand, there is provided on at least one side of the film, in addition to the usual picture area and sound track, a further separate track for controlling the sound atmosphere. We will call hereinafter this supplementary track a pilot track? and it may be provided on the part of the film carrying the perforations which latter do not trouble operation if sufficient care is exercised as is amply shown by experience; on the other hand, according to said methods, said pilot track cooperates with a light box and with a photocell controlling a preliminary pilot amplifier 'the input of which is modulated by the usual sound reading means, said amplifier energizing either a discriminator provided with two outputs modulating, in the desired proportion as defined by the pilot track, the usual system including the amplifier and screen loud-speakers and a separate system including an amplifier and a sound atmosphere loud-speaker or else said pilot amplifier energizes a selector system located at the output of the usual amplifier.

The pilot track may be of the constant density, variable breadth type or else of the variable density type with a constant breadth or again'it may be of the variable frequency type for removing any sensitivity of the system to dust,

2 scratches, oil deposits or the like soiled parts of the film.

Our invention has also for its object the execution of a device for drawing the pilot track on a standard sound track, said device being remarkable in particular through the fact that it includes means for drawing a track with a variable breadth and constant density under the control of a relay that is in its turn controlled by hand by an operator entrusted, before public projection, with the preparation of the film providing a sound atmosphere.

Another object of our invention consists in exeouting an arrangement for reading a pilot track, which arrangement is remarkable in particular by the fact that it includes a photoelectric reading system with a photocell and an energizing lamp, and a pilot amplifier directing towards the different loud-speakers in the hall the modulation produced by the usual sound track of the film, said pilot amplifier being adapted to this purpose to control differentially either the input into a plurality of amplifiers of the output of the usual amplifier, the pilot amplifier acting in any case after the manner of a switch.

Our invention covers also by way of a new article of manufacture the sound film including a pilot track serving for the execution of an automatic sound atmosphere.

The above referred to means allow obtaining the most varied sound atmosphere effects such as the noise of a crowd, sound travelling, a panoramic sound view, noise from beyond thescreen, stereoscopic noises etc. In the case Where the. pilot track is of the variable frequency type, thearrangement serving for incorporating it to the film may consist in inking wheels-the peripheries of which are provided with inking teeth arranged at intervals that vary according to the wheels considered, said wheels being brought separately into contact with .the film by the operator entrusted with the. progization of the cell controlling the means producing the sound atmosphere.

Said screening means are preferably constituted by a toothed drum containing the lamp energizing the photocell controlling the sound atmosphere and showing at the points corresponding to the intervals between the perforations in .the film openings for the passage of the energizinglight bundle acting on the cell considered.

Means for gradually energizing the loudspeakers are inserted in the circuits feeding same to prevent said loud-speakers from being started too abruptly. Said gradually energizing means are preferably constituted by'a rocking mercury rheostat.

Further features and objects of our invention will appear in the reading of the following description, given out by way of example, of certain embodiments without same forming in any manner a limitation to our invention. Said embodirnents are illustrated in accompanying drawings wherein:

Fig. '1 is a general diagram of the arrangement includin means for drawing-the pilot track and a system for producing the sound atmosphere and the sound at the screen.

Fig. 2 is a diagrammatic perspective view of the "track drawing means and of the reading means for the track producing the sound atmosphere or pilot track, together with a part or" the sound film and pilot track.

Fig. 3 is a diagrammatic view, partly in perspective,- of a modification of the means producingthe pilot track. Fig. 4 is adiagrammatic view of a modification of a photo-electric reader for the pilot track.

- Fig. 5 is a rough diagram of a pilot amplifier.

Fig. 6, '7 and 8 show three half-sections of a sound film carrying pilot tracks for three different frequencies.

Fig. 9 illustrates the recording means for a track with three pilot frequencies.

Fig. 10 is a cross-section of the screening means for the driving perforations of the film.

Fig. 11 is a perspective view of a relay with three vibrating blades.

Fig. I 12 illustrates an arrangement for the gradual feedin of one of the loud-speakers.

Lastly Fig. 13 is a diagram illustrating a rec ti'fying amplifier with the auxiliary parts of the means producing the sound atmosphere.

In Fig. 1, we have shown at I the cinematographic projecting apparatus with its upper and lower film holders 2 and 3, at 4 the photocell of the usual sound reader, at 5 the light box enclosing the lamp energizin the cell 4 and at 5 the sound film with its perforated edges 6 and E", the usual sound track 5" and the area carrying the photographic pictures 5 The photocell i is connected with the input of the p'ilotamplifier 7 including two outputs modu lating on one hand the normal screen amplifier 8 feeding the screen loud-speaker or loud-speakers 9 and-on the other hand a special amplifier IB feeding the loud-speaker or loud-speakers H producing the sound atmosphere.

Beyond the usual sound reader 45'is provided a system including means I2 for drawing the pilot tra'ck'and'a'reader for said pilot track constituted by a photocell i3 with-its light box M containing the corresponding energization lamp.

opposite directions the-modulation appliedto the normal amplifier 8 and the modulation applied to the sound atmosphere amplifier iii.

In order to execute the pilot track on film 6, it'is possible as shown in Fig. 2 to make use of drawing means including a drawing pen l5 of a variable spacing constituted by a stationary arm and a movable arm l5" pivctally secured l5" to said stationary arm, the inthe ink potentiometer 22. the brush 23 of which is connected with the other terminal of the current supply considered. 1

The location of the inking pen nose I5 is adjusted so as to comeinto contact with the film "6 along one of the perforated edges of the latter, say '6".

This track drawing means operates as follows: for preparing the film before public projection thereof, the operator entrustedwithithe drawing of the pilot track begins by projecting normally said film and controls the handle .of the brush with a view-to measuring the modulated power feeding the loud-speakers for the :screen on one hand and for the sound atmosphere .on the other, the energy fed to "said sets of loud-speakersbeing as disclosed hereinafter provided in opposite =r.iirections.

The operation of the brush 2'3 produces-a more or less considerable :spacing between the arms of the drawin pen i .5 that draws on the perforated marginal area 6" :of the film '6 a line forming the pilot track '25.

The result of this drawing .is "immediately us certained by the operator who in case of any defect or error in estimation may at least wipe away the .part of the pilot track that is not satisfactory and begin the operation over again. As a matterof fact, the reader of the pilot track that energizes the pilot amplifier is located immediately beyond the-drawing means. In Fig. 2, it is immediately apparent that $3 designates said reader :for the pilot track and I4 is the lamp energizing said cell through the condenser 26 and the slotted screen 27.

As apparent from Fig.3, the reader of the pilot track maybe of the reflecting type including a light box I ia with the lamp M, a condenser 26a, a mirror 21a and .a photocell 13a in its casing 28.

The means drawing the pilot track may also be executedas illustrated in Fig. 4. In this form :of execution, the drawing means 29 which .is'of :a rotary type includes two sectors 29' and 29" connected with one another :along 'a radial line and forming 'a variable angle with reference to one another, the feeding with ink being obtained through a container H5. The angular position of the drawing means =29 is controlledby a spindle 36 with which it is rigid and on'which is secured the rotor SE of the motor '32 of which the field or stator 33 is fed by a source of direct current controlled through 'a 'rheostat that is not illustrated and that maybe controlled by the one):- ator who-has to draw the pilot track.

The pilot amplifier 1 replacing the usual preliminary cell amplifier, modulating the power amplifier of the screen loud-speakers, comprises a modulation input connected with the photocell 4 of the usual reader of the sound track 6" and an input for controlling the production of the sound atmosphere, connected with the cell !3 of the reader of the pilot track 25. The cell 4 energizes through the agency of an amplifying tube 34 the two modulating grids mounted in parallel of two octode tubes 3536 modifying the depth of modulation through a modification of the voltage applied to each suppressor grid under the control of the pilot cell I3; the anodes of these two octodes feed directly the screen amplifier 8 and the amplifier for sound atmosphere Ill. The cell I3 energizes through the two amplifying tubes 37 and 33 two symmetrical chains including, the former an amplifying tube 39 and a detecting tube 40 controlling the voltage of the suppressor grid in the tube 35 while the second chain includes an amplifying tube 4| and a detecting tube 42 controlling the voltage of the suppressor grid of the tube 36, the grid bias in the two detecting tubes 40 and 42 being different from one another.

The depths of modulation collected at the output of each tube 35 and 36 vary thus in opposite directions with reference to one another under the control of the pilot cell l3.

In Figs. 6 to 8 the pilot-frequency track of variable frequency 4| includes an opaque line of constant width throughout the solid portions separating the perforations of the film 42. According as to whether the track is produced throughout all the intervals separating the perforations (Fig. 6) 'or only over one interval out of two (Fig. 7) or one interval out of three (Fig. 8), the pilot track of a standard sound film advancing at the rate of 96 perforations per second will produce a frequency of 96, 48 or 32 periods per second. Of course it is possible to provide any desired frequency underneath 96 periods per second.

In order to execute the recording of such a pilot track, it is possible to use an inking device of the type illustrated in Fig. 9 and including three wheels 44a, 44b and 440 dipping into an ink bath contained in a vat 43. Said wheels are provided with inking teeth distributed over the periphery of said wheels at different intervals for producing on the film t2 traces or impressions 4! at different spacings as disclosed hereinabove.

The inking wheels 44a, 44b and 440 may be controlled by electromagnets 45a, 45b and 450' the circuits of which arev controlled by the operator entrusted with the formation of the pilot track.

The reader of the pilot track of variable frequency comprises as shown at Fig. a toothed drum 46 the teeth of which engage the perforations 42a of the film 42; said drum is provided between its teeth with ports 4l allowing the passage of the light beam sent out of the light source 48 arranged inside said drum and serving for the energization of the photocell 49 solely at the points corresponding to the intervals between the perforations of the film.

Under such conditions, the photocell 49 may be energized only if the above intervals between the perforations are not provided with any pilot impressions.

As apparent from Fig. 13, the cell 49 feeds a rectifying amplifier 50 including a low-pass filter 5i eliminating the frequencies above 100 periods per second.

The rectifying output tube of the rectifying amplifier energizes a relay 52 (Figs. 11 and 13) provided with a plurality of vibrating blades (three in the example illustrated), tuned to the 6' pilot frequencies say the frequencies of 96, 48 and 32 periods per second in the case of the choice of frequencies considered hereinabove.

Each of the vibrating blades 52a, 52b and 52c controls means 53 for the gradual energization of the loud-speaker 54 either for the picture screen or for the means producing the sound atmosphere.

The arrangement 53 referred to (Figs. 12 and 13) includes a relay 53a the circuit of which is controlled by the corresponding vibrating blade 52a and the vane 53b of which provides for the rocking of a mercury rheostat formed by an arcuate tube 530 enclosing a drop of mercury 53d, wherein is located a main electrode 53c and a certain number of auxiliary electrodes 53] inter connected through resistances 539.

As long as the electromagnet relay 53a. is not energized, the tube 530 slopes towards the right and the drop of mercury 53d lies on the right hand side thereof. As soon as the relay is energized the tube 530 slopes towards the left and the drop of mercury is displaced towards the left in a fraction of a second while it establishes the contact between the electrode 53c and the electrode 53) so as to short-circuit in succession the resistances in series 539. The loud-speaker 54 is thus started without any jerks and in a gradual manner.

It is apparent that with the improved arrangement disclosed hereinabove the screen and the sound atmosphere loud-speakers are fed with modulated current in a manner that is perfectly independent of the imperfections of the pilot track, which imperfections may be due for instance to wear.

Obviously the examples of execution of the above described arrangements as illustrated in accompanying drawings have been given out merely by way of exemplification and many detail modifications may be brought thereto without unduly Widening the scope of the invention. Thus it is possible to provide two pilot tracks controlling a sound equipment for the screen and two equipments for sound atmosphere; it is also possible to provide for the drawing of the pilot track. on a separate strip forming a control strip for the sound atmosphere, that is unwound in synchronism with the sound film inside an apparatus that is separate from the extent projecting means. Similarly it is possible to mount at the output of the pilot amplifier a mechanical selector for the modulated energy produced by the usual amplifier.

What we claim is:

1. Arrangement for drawing on a sound film at least one pilot track comprising in combination means for transporting said sound film along a predetermined path; a vat adapted to containa liquid capable of recording said pilot track, said vat arranged near the path of said film; a plurality of toothed wheels each having its teeth arranged at different spacings and arranged so as to dip into liquid in said vat; axles carrying said toothed wheels movably toward and away from said predetermined path of said'sound film; magnetic cores mechanically connected with said axles of said toothed Wheels; coils adapted to control said magnetic cores so as to move the teeth of said wheels into engagement with said sound film, when energized; and means for selectively connecting said coils to a source of electric current.

2. Arrangement for drawing on a sound film at least one pilot track comprising in combination means for transporting said sound film along a predetermined film path; a plurality of toothed aster;

7"? Wheels arrangedt'along said-1 predetermined film? pathiandieaeh' having printing teeth arranged; at different spacings. for. printing said pilot" track;- meansi-supporting saidtoothed. wheels. independe'ntlyofieach.otherrand movable between inoperr ative'ipositi'on spacedfrom said soundfilm= and operative position in engagement with :saidv sound; film: printing saidpilot track on theisame; and manually operable means for selectivelyxmoving said tootlied' ivheelsfrom inoperative into .op.era';-- g

tive position, Whenever'desired;

it. An arrangement .for drawingon a previously. developed: sound film having asoundtrack at least one-1 pilot .-traok comprising in. combination means for transportingsaid sound filmalong: a" predetermined path; sound reproducing means forq'eproducingthe sound-recorded bysaid sound track; at least. one pilottrack producingmember arrangedlalongsaid predetermined path; means supporting: said pilot 1 trackv producing: member movablebetween. inoperative position. spaced from said predetermined path and operative position: moved toward said predetermined path in engagement-With a soundfilm passing along'the' same-so as to be adapted-tozproduce'a pilot track onthe-same; manually operable actuating means for moving said pilot track producing: member from inoperative into operative position, whenever desirecl'; photoelectric means arranged along said predetermined path after said pilot track. producing member'so as tozcreate electric cur+ rent v'ariations .correspondingrto variations of the pilot track produced by said pilot tracksproducing member; andimeans' for varying. the sound repro-.- duced by said sound reproducing means. in accordance with' said electric current variations;

4. An arrangement fordrawington a previously developed sound film having a. sound track. at; least one: pilot track: comprising? in combinationv means'tfor:transporting said sound film along. a predetermined film" path; sound reproducingmeans for reproducing the sound recorded by said soundtrack; 2; vat adapted to' contain a liquidcapable of recording said pilot track, saidvat. arranged near-thepath of said film; a pluralityortoothed'Wheels"each having its teeth-aw rangedat: differentspacings anda-rranged so" as to diplintoliquid in saidvat; axles carrying :said toothed Wheels movablytoward. and away: from said; predetermined path of said sound film; magnetic cores mechanically connected: with saidaxles of said'toothed wheels; coils adapted: to control said magnetic cores so as to move the; teeth of said Wheels into engagement; with. said soundfilm, when energized; means for selectively connectingsaid coils-to a source'of' electric current-g: photoelectric means arranged along said predetermined, film path after said. toothed Wheels-so as to createselectric current variations corresponding to variationsv of the. pilot track produced by one of? said. toothed Wheels; and meansforvarying the sound reproduced-by said sound reproducing; means in accordance with said" electric current variations.

5. A-niarrangement for drawing onapreviously developed sound film having a sound track at least. one: pilot? track comprising: in combination;

means: for transporting said; sound. film along a:

predetermined; films path; means: for reproduceing: theisoundrecorded bysaid sound track; a;

luralityrof printingidevices: arranged along said? predeterminedfilm path and each having printe ingxprojections for. printing. difierent pilot: tracks; means supporting said. printing devices:-

independently of eachv other and: movable be? tweeniinoperative;position spaced fromgsaid pro-.- determined" film path and; operative position; moved towardsaid predetermined filmpath in engagement. with asound film passing. along the same: so, as. to be: adapted ;to, print a: pilot; track onthesame; manually operableactuating means:

foiz'seleotivelymoving saidzprinting devices from. inoperative into" operative; position; Whenever desired}: photoelectric; means arranged. along: said predeterminedifilm path; after said, rinting: devices: seas toicreateelectric current variations:-

corresponding" to; variations: of said. pilot; track produced by one of said printing devices; and? electrical means influenced-by said electric currentwariations foryvaryingtthe sound reproduced by saidsoun'd reproducingmeans in accordance with said electric current. variations;

6. An; arrangement for. drawing on a previousi'y developed sound filmhaving" a. sound track: at" least one; pilot track :comprising in com-.

binationmeans :for: transporting said; sound film:

along: a: predetermined path; sound-f reproducing means for reproducing the: sound. recorded by: said soundtrack; at:1east;one pilot *trackxdrawing:

member arranged along said predetermined. path, means supportingsaidpilot track produceing member" movable between inoperative posi-v tion' spacedifromi said predetermined path: and:

operative position moved toward said predetermined path. in engagement? with a sound filmpassing along the same so asfltoibeadaptedio draw-a pilot-track-onthe-same, and: manually operable actuating means for moving i said pilot track: producing. member from: inoperative into operativeposition whenever desired.

GUY CLUTIER. MARC ASSA-DA.

REFERENCES CITED The followingreferences areof record" in the file of this patent:

UNITED STATES" PATENTS Number Name Date- 267,967 Anderson Nov. 21, 1882. 1,759,581. Kwartin May 20, 193%). 1,975,928 Eldred W Oct. 9, 193.4: 2,022,665 Halstead- Dec. 3,19% 2,054,216- Fuller Sept. 15, 1936 2,066,889 Eissfeldt Jan. 5; 1937 2,199,559 Dawson May- 7, 1940 2,228,643v Rudkin Jan. 14, 1941 2,238,947 Ross Apr. 22, 1941 2,361,490 Mueller Oct. 31, 1944 2,367,394 Levinson Jan. 16, 1945 2,385,861 Jones Oct. 2,- 1945 

